Loading on pin

I'm a bit rusty on partial uniform loading on a pin. I want to find the minimum diameter a cold rolled steel pin has to be using a factor of safety of 2 with a loading of 25000 lbs. The pin in the picture is welded between two plates (the right plate bends in and is welded to the left plate below the pin) . These plates are welded to a box (another pin is located on the opposite side of the box). A hook grabs onto this pin. I've tried finding equations regarding partial uniform loading. The equations I've turned up show the center piece the same width as the gap.

Thanks for the paper. However, this does not show how the stress changes if the clevis has two different thicknesses. I guess I could take the worst case scenario and use the lesser of the two thicknesses for my t1.

Your scenario is challenging to find an analytical solution for because there is a gap between the inner and outer clevis which will cause a bending load on the pin, and the outer clevis's plates are asymmetric in thickness.

Have you considered making some assumptions to simplify your modeling task? I think you could consider a beam bending model of just the pin with a simply-supported beam. This would be a "worst-case" analysis because the pin would not be stiffened by the clevis in this case. Otherwise, FEA really may be your best option.